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Diagnostic Trouble Code (DTC) P0621

Generator L - Terminal Circuit

Circuit Description

The engine control module (ECM) applies a signal voltage to the Generator L terminal circuit to control the load of the generator on the engine. A Generator L terminal circuit DTC sets if the ECM detects the Generator L circuit voltage is outside the specified range for a predetermined set of parameters.

Conditions for Running the DTC

Conditions for Setting the DTC

Action Taken When the DTC Sets

Conditions for Clearing the MIL/DTC

DTC P0621 - Generator L - Terminal Circuit

Step Action Value(s) Yes No
1
Did you perform the Diagnostic System Check?
-
Go to Step 2
Go to "Diagnostic System Check"
2
  1. Switch off the ignition for 30 seconds.
  2. Operate the vehicle within the conditions for running the DTC.
  3. Using the Scan Tool, select the DTC display function.
Did the DTC P0621 fail this ignition?
-
Go to Step 3
-
3
Test the charging system for any fault condition that may cause incorrect generator operation.
Did you find and correct the condition?
-
Go to Step 6
Go to Step 4
4
Test the generator L signal circuit for a high resistance, open circuit, or short to ground fault condition.
Did you find and correct the condition?
-
Go to Step 6
Go to Step 5
5
Replace the ECM.
Did you complete the replacement?
-
Go to Step 6
-
6
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Setting the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
-
Go to Step 2
Go to Step 7
7
Check if any additional DTCs are set.
Are there any DTCs that have not been diagnosed?
-
Go to applicable DTC table
System OK

Diagnostic Trouble Code (DTC) P0627

Fuel Pump Relay Control Circuit Open

Circuit Description

When the ignition switch is turned ON, the ECM will activate the fuel pump relay and run the in-tank fuel pump.
The fuel pump will operate as long as the engine is cranking or running and the ECM is receiving ignition reference pulses.

Conditions for Running the DTC

Conditions for Setting the DTC

Action Taken When the DTC Sets

Conditions for Clearing the MIL/DTC

Diagnostic Aids

An Intermittent problem may be caused by a poor connection, rubbed through wire insulation, or wire that is broken inside the insulation.
Any circuitry, that is suspected as causing the complaint, should be thoroughly checked for the following conditions.

DTC P0627 - Fuel Pump Relay Control Circuit Open

Step Action Value(s) Yes No
1
Perform the Diagnostic System Check.
Is the system check complete?
-
Go to Step 2
Go to "Diagnostic System Check"
2
  1. Turn the ignition switch to LOCK for 10 seconds.
  2. Turn the ignition switch to ON.
  3. Listen for in-tank fuel pump operation.
Does the fuel pump operate?
2 seconds
Go to "Diagnostic Aids"
Go to Step 3
3
  1. Turn the ignition switch to ON.
  2. Disconnect the fuel pump relay.
  3. Connect a test light between the fuel pump relay connector terminal 86 and ground.
  4. Turn the ignition switch to ON.
Is the test light ON?
-
Go to Step 4
Go to Step 10
4
  1. Turn the ignition switch to ON.
  2. Disconnect the fuel pump relay.
  3. Connect a test light between the fuel pump relay connector terminal 85 and B+.
  4. Turn the ignition switch to ON.
Is the test light ON?
-
Go to Step 5
Go to Step 9
5
  1. Turn the ignition switch to LOCK.
  2. Connect a test light between the fuel pump relay connector terminal 30 and ground.
Is the test light ON?
-
Go to Step 6
Go to Step 8
6
Check for an open in the wire between the fuel pump relay connector terminal 87 and fuel pump connector.
Is the problem found?
-
Go to Step 7
Go to Step 8
7
  1. Repair the wire between the fuel pump relay connector terminal 87 and fuel pump connector terminal 4.
  2. Install the fuel pump relay.
  3. Turn the engine OFF for 10 seconds.
  4. Clear any DTCs from ECM.
  5. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
Go to Step 14
-
8
  1. Replace the fuel pump relay.
  2. Turn the ignition OFF for 10 seconds.
  3. Clear any DTCs from ECM.
  4. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
Go to Step 14
Go to Step 9
9
Check for an open wire between the fuel pump relay connector terminal 85 and the ignition after key ON(IGN 1).
Is the problem found?
-
Go to Step 11
Go to Step 10
10
Check for an open wire between the fuel pump relay connector terminal 86 and the ECM connector J1 terminal 51.
Is the problem found?
-
Go to Step 12
Go to Step 13
11
  1. Repair the wire between the fuel pump relay connector terminal 85 and the ignition key ON (IGN1).
  2. Install the fuel pump relay.
  3. Turn the ignition OFF for 10 seconds.
  4. Clear any DTCs from ECM.
  5. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
System OK
Go to Step 13
12
  1. Repair the wire between the fuel pump relay connector terminal 86 and the ECM connector J1 terminal 51.
  2. Install the fuel pump relay.
  3. Turn the ignition OFF for 10 seconds.
  4. Clear any DTCs from ECM.
  5. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
System OK
Go to Step 13
13
  1. Replace the ECM.
  2. Turn the ignition OFF for 10 seconds.
  3. Clear any DTCs from ECM.
  4. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
System OK
Go to Step 14
14
  1. Using the scan tool, clear the DTCs.
  2. Start the engine and idle at normal operating temperature.
  3. Operate the vehicle within the conditions for setting this DTC ad specified in the supporting text.
Does the scan tool indicate that this diagnostic has run and passed?
-
Go to Step 15
Go to Step 2
15
Check if any additional DTCs are set.
Are any DTCs displayed that have not been diagnosed?
-
Go to applicable DTC table
System OK

Diagnostic Trouble Code (DTC) P0628

Fuel Pump Relay Control Circuit Low Voltage

Circuit Description

When the ignition switch is turned ON, the ECM will activate the fuel pump relay and run the in-tank fuel pump.
The fuel pump will operate as long as the engine is cranking or running and the ECM is receiving ignition reference pulses.

Conditions for Running the DTC

Conditions for Setting the DTC

Action Taken When the DTC Sets

Conditions for Clearing the MIL/DTC

Diagnostic Aids

An Intermittent problem may be caused by a poor connection, rubbed through wire insulation, or wire that is broken inside the insulation.
Any circuitry, that is suspected as causing the complaint, should be thoroughly checked for the following conditions.

DTC P0628 - Fuel Pump Relay Control Circuit Low Voltage

Step Action Value(s) Yes No
1
Perform the Diagnostic System Check.
Is the system check complete?
-
Go to Step 2
Go to "Diagnostic System Check"
2
  1. Turn the ignition switch to LOCK for 10 seconds.
  2. Turn the ignition switch to ON.
  3. Listen for in-tank fuel pump operation.
Does the fuel pump operate?
2 seconds
Go to "Diagnostic Aids"
Go to Step 3
3
  1. Turn the ignition switch to ON.
  2. Disconnect the fuel pump relay.
  3. Connect a test light between the fuel pump relay connector terminal 86 and ground.
  4. Turn the ignition switch to ON.
Is the test light ON?
-
Go to Step 4
Go to Step 10
4
  1. Turn the ignition switch to ON.
  2. Disconnect the fuel pump relay.
  3. Connect a test light between the fuel pump relay connector terminal 85 and B+.
  4. Turn the ignition switch to ON.
Is the test light ON?
-
Go to Step 5
Go to Step 9
5
  1. Turn the ignition switch to LOCK.
  2. Connect a test light between the fuel pump relay connector terminal 30 and ground.
Is the test light ON?
-
Go to Step 6
Go to Step 8
6
Check for a short to ground in the wire between the fuel pump relay connector terminal 87 and fuel pump connector.
Is the problem found?
-
Go to Step 7
Go to Step 8
7
  1. Repair the wire between the fuel pump relay connector terminal 87 and fuel pump connector terminal 4.
  2. Install the fuel pump relay.
  3. Turn the engine OFF for 10 seconds.
  4. Clear any DTCs from ECM.
  5. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
Go to Step 14
-
8
  1. Replace the fuel pump relay.
  2. Turn the ignition OFF for 10 seconds.
  3. Clear any DTCs from ECM.
  4. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
Go to Step 14
Go to Step 9
9
Check for a short to ground wire between the fuel pump relay connector terminal 85 and the ignition after key ON(IGN 1).
Is the problem found?
-
Go to Step 11
Go to Step 10
10
Check for a short to ground wire between the fuel pump relay connector terminal 86 and the ECM connector J1 terminal 51.
Is the problem found?
-
Go to Step 12
Go to Step 13
11
  1. Repair the wire between the fuel pump relay connector terminal 85 and the ignition key ON (IGN1).
  2. Install the fuel pump relay.
  3. Turn the ignition OFF for 10 seconds.
  4. Clear any DTCs from ECM.
  5. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
System OK
Go to Step 13
12
  1. Repair the wire between the fuel pump relay connector terminal 86 and the ECM connector J1 terminal 51.
  2. Install the fuel pump relay.
  3. Turn the ignition OFF for 10 seconds.
  4. Clear any DTCs from ECM.
  5. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
System OK
Go to Step 13
13
  1. Replace the ECM.
  2. Turn the ignition OFF for 10 seconds.
  3. Clear any DTCs from ECM.
  4. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
System OK
Go to Step 14
14
  1. Using the scan tool, clear the DTCs.
  2. Start the engine and idle at normal operating temperature.
  3. Operate the vehicle within the conditions for setting this DTC ad specified in the supporting text.
Does the scan tool indicate that this diagnostic has run and passed?
-
Go to Step 15
Go to Step 2
15
Check if any additional DTCs are set.
Are any DTCs displayed that have not been diagnosed?
-
Go to applicable DTC table
System OK

Diagnostic Trouble Code (DTC) P0629

Fuel Pump Relay Control Circuit High Voltage

Circuit Description

When the ignition switch is turned ON, the ECM will activate the fuel pump relay and run the in-tank fuel pump.
The fuel pump will operate as long as the engine is cranking or running and the ECM is receiving ignition reference pulses.

Conditions for Running the DTC

Conditions for Setting the DTC

Action Taken When the DTC Sets

Conditions for Clearing the MIL/DTC

Diagnostic Aids

An Intermittent problem may be caused by a poor connection, rubbed through wire insulation, or wire that is broken inside the insulation.
Any circuitry, that is suspected as causing the complaint, should be thoroughly checked for the following conditions.

DTC P0629 - Fuel Pump Relay Control Circuit High Voltage

Step Action Value(s) Yes No
1
Perform the Diagnostic System Check.
Is the system check complete?
-
Go to Step 2
Go to "Diagnostic System Check"
2
  1. Turn the ignition switch to LOCK for 10 seconds.
  2. Turn the ignition switch to ON.
  3. Listen for in-tank fuel pump operation.
Does the fuel pump operate?
2 seconds
Go to "Diagnostic Aids"
Go to Step 3
3
Check for short to battery voltage or low voltage in the wire between the fuel pump relay connector terminal 87 and fuel pump connector 4.
Is the problem found?
-
Go to Step 7
Go to Step 5
4
  1. Repair the wire between the fuel pump relay connector terminal 87 and fuel pump connector terminal 4.
  2. Install the fuel pump relay.
  3. Turn the engine OFF for 10 seconds.
  4. Clear any DTCs from ECM.
  5. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
Go to Step 11
-
5
  1. Replace the fuel pump relay.
  2. Turn the ignition OFF for 10 seconds.
  3. Clear any DTCs from ECM.
  4. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
Go to Step 11
Go to Step 6
6
Check for short to battery voltage wire between the fuel pump relay connector terminal 85 and the ignition after key ON(IGN 1).
Is the problem found?
-
Go to Step 8
Go to Step 7
7
Check for an open wire between the fuel pump relay connector terminal 86 and the ECM connector J1 terminal 51.
Is the problem found?
-
Go to Step 9
Go to Step 10
8
  1. Repair the wire between the fuel pump relay connector terminal 85 and the ignition key ON (IGN1).
  2. Install the fuel pump relay.
  3. Turn the ignition OFF for 10 seconds.
  4. Clear any DTCs from ECM.
  5. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
System OK
Go to Step 10
9
  1. Repair the wire between the fuel pump relay connector terminal 86 and the ECM connector J1 terminal 51.
  2. Install the fuel pump relay.
  3. Turn the ignition OFF for 10 seconds.
  4. Clear any DTCs from ECM.
  5. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
System OK
Go to Step 10
10
  1. Replace the ECM.
  2. Turn the ignition OFF for 10 seconds.
  3. Clear any DTCs from ECM.
  4. Turn the ignition switch to ON.
Does the fuel pump operate?
2 seconds
System OK
Go to Step 11
11
  1. Using the scan tool, clear the DTCs.
  2. Start the engine and idle at normal operating temperature.
  3. Operate the vehicle within the conditions for setting this DTC ad specified in the supporting text.
Does the scan tool indicate that this diagnostic has run and passed?
-
Go to Step 12
Go to Step 2
12
Check if any additional DTCs are set.
Are any DTCs displayed that have not been diagnosed?
-
Go to applicable DTC table
System OK

Diagnostic Trouble Code (DTC) P0630

Vin not Programmed or Mismatched - Engine Control Module (ECM)

Circuit Description

The engine control module (ECM) stores the vehicle identification number (VIN). If there is not a VIN stored in the ECM, this DTC sets.

Conditions for Running the DTC

Conditions for Setting the DTC

Action Taken When the DTC Sets

Conditions for Clearing the MIL/DTC

DTC P0630 - Vin not Programmed or Mismatched - Engine Control Module (ECM)

Step Action Value(s) Yes No
1
Did you perform the Diagnostic System Check?
-
Go to Step 2
Go to "Diagnostic System Check"
2
  1. Install a scan tool.
  2. Turn the ignition ON, with the engine OFF.
  3. With the scan tool, observe the Vehicle Identification Number (VIN) Information parameter.
Is the VIN Information stored?
-
Go to Step 3
Go to Step 4
3
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Turn ON the ignition.
  4. Operate the vehicle within the Conditions for Setting the DTC.
Does the DTC run and pass?
-
Go to Step 7
Go to Step 5
4
Using the scan tool, write the VIN information on the ECM.
Did you complete VIN writing?
-
Go to Step 6
-
5
Replace the ECM.
Did you complete the replacement?
-
Go to Step 6
-
6
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Turn ON the ignition.
  4. Operate the vehicle within the Conditions for Setting the DTC.
Does the DTC run and pass?
-
Go to Step 7
Go to Step 2
7
Check if any additional DTCs are set.
Are any DTCs displayed that have not been diagnosed?
-
Go to applicable DTC table
System OK

Diagnostic Trouble Code (DTC) P0633

Immobilizer Key not Programmed

Circuit Description

When learning the fuel enable password, as well as the challenge and response sequence, the engine control module (ECM) is placed in learn mode. DTC P0633 will set automatically as an indicator that the system is in learn mode and not as a fault indicator. Once the password and challenge/response are learned, learn mode will be exited and the DTC cleared. If the ECM does not exit learn mode, P0633 will remain current and indicate a fault.

Conditions for Running the DTC

Conditions for Setting the DTC

or

Action Taken When the DTC Sets

Conditions for Clearing the MIL/DTC

Diagnostic Aids

The "key" referenced in the DTC descriptor does not refer to the vehicle key. In this case, "key" is referring to the challenge response.

DTC P0633 - Immobilizer Key not Programmed

Step Action Value(s) Yes No
1
Perform the Diagnostic System Check.
Is the system check complete?
-
Go to Step 2
Go to "Diagnostic System Check"
2
  1. Turn the ignition switch to LOCK.
  2. Install a scan tool to the data link connector (DLC).
  3. Turn the ignition switch to ON.
  4. Check if other immobilizer related DTCs are set.
Are any DTCs displayed?
-
Go to Applicable DTC table
Go to Step 3
3
Perform the Programming Theft Deterrent System Components. Refer to 9T2 Immobilizer Anti-Theft System
Does the DTC run and pass?
-
Go to Step 5
Go to Step 4
4
Replace the ECM.
Is the replace complete?
-
Go to Step 5
-
5
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Setting the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
-
Go to Step 2
Go to Step 2
6
Check if any additional DTCs are set.
Are any DTCs displayed that have not been diagnosed?
-
Go to applicable DTC table
System OK

Diagnostic Trouble Code (DTC) P0638

Throttle Actuator Control (TAC) Command Performance

Circuit Description

The engine control module (ECM) controls the throttle valve by applying a varying voltage to the control circuits of the throttle actuator control (TAC) motor. The ECM monitors the duty cycle that is required to actuate the throttle valve. The ECM monitors the throttle position (TP) sensors 1 and 2 to determine the actual throttle valve position.

Conditions for Running the DTC

Conditions for Setting the DTC

Action Taken When the DTC Sets

Conditions for Clearing the MIL/DTC

Diagnostic Aids

DTC P0638 - Throttle Actuator Control (TAC) Command Performance

Step Action Value(s) Yes No
1
Did you perform the Diagnostic System Check?
-
Go to Step 2
Go to "Diagnostic System Check"
2
  1. Turn On the ignition, with the engine OFF.
  2. Clear the DTCs with a scan tool.
  3. Start the engine.
  4. Perform the following tests:
    • Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times.
    • Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times.
  5. Observe the DTC information with a scan tool.
Did DTC P0121, P0122, P0123, P0221, P0222, or P0223 fail this ignition?
-
Go to applicable DTC table
Go to Step 3
3
Did DTC P0638, and/or P2119 fail this ignition?
-
Go to Step 5
Go to Step 4
4
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Setting the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
-
Go to Step 5
Go to "Diagnostic Aids"
5
  1. Turn OFF the engine.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the TP sensor 1 voltage parameter with a scan tool.
Is the voltage within the specified range?
0.40-0.80 V
Go to Step 6
Go to "DTC P0121"
6
Observe the TP sensor 2 voltage parameter with a scan tool.
Is the voltage within the specified range?
4.7-4.1 V
Go to Step 7
Go to "DTC P0221"
7
  1. Disconnect the throttle body harness connector.
  2. Turn ON the ignition, with the engine OFF.
  3. Measure the voltage of the throttle actuator control (TAC) motor control 1 and TAC motor control 2 circuits of the throttle actuator control motor with a DMM connected to the engine control module (ECM) housing.
Is the voltage within the specified range for both circuits?
2-4 V
Go to Step 8
Go to Step 9
8
  1. Turn OFF the ignition.
  2. With a Test Lamp connected to ground, prove the TAC motor control 1 and TAC motor control 2 circuit of the throttle body harness connector.
  3. Turn ON the ignition for about 5 seconds and then turn OFF the ignition while you observe the test lamp. Repeat this procedure, as necessary.
Does the test lamp turn ON and then OFF each time the ignition is cycled?
-
Go to Step 12
Go to Step 11
9
Is the voltage less than the specified value?
2 V
Go to Step 10
Go to Step 14
10
Test the TAC motor control circuit that measured below the specified value for an open or a short to ground.
Did you find and correct the condition?
-
Go to Step 18
Go to Step 13
11
  1. Turn OFF the ignition.
  2. Disconnect the ECM.
  3. Test for continuity between the TAC motor control 1 and TAC motor control 2 circuit of the throttle body harness connector.
Is there continuity?
-
Go to Step 15
Go to Step 13
12
Test for shorted terminals and for poor connections at the throttle body connector.
Did you find and correct the condition?
-
Go to Step 18
Go to Step 16
13
Test for shorted terminals and for poor connections at the ECM.
Did you find and correct the condition?
-
Go to Step 18
Go to Step 17
14
Repair the appropriate TAC motor control circuit for a short to voltage.
Did you complete the repair?
-
Go to Step 18
-
15
Repair the short between the TAC motor control circuits 1 and 2.
Did you complete the repair?
-
Go to Step 18
-
16
Replace the throttle body assembly.
Did you complete the replacement?
-
Go to Step 18
-
17
Replace the ECM.
Did you complete the replacement?
-
Go to Step 18
-
18
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Setting the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
-
Go to Step 2
Go to Step 19
19
Check if any additional DTCs are set.
Are there any DTCs that have not been diagnosed?
-
Go to applicable DTC table
System OK


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